Call-distributing system



5 SHEETS SHEET h FILED JUNE 20, 1922.

. Feb, 27, 1923.

m ls

L. Poumkowsxv.

CALL DISTRIBUTING SYSTEM.

FILED JUNEZO. 1922.

5 SHEETSSHEET 2.

2 Mvmfm' Zg Zm Pam r0 My.

Feb. 27, 1923; v 1,446,582.

I L- POLINKOWSKY.

CALL DISTRIBUTING SYSTEM. v FILED JUNE 20. 1922. 5 SHEETS-SHEET &.

W e/11w? 14km; Pa/M/rawsky by Feb. 27, 1923.

L. POLINKOWSKY.

CALL DISTRIBUTING SYSTEM. FILED IUNEZO. 1922.

5 SHEETS-SHEET 4- hwhfo/c' 140a Pa/m/rows/ry.

'A/ry L. POLIN KOWSKY.

CALL DISTRIBUTING SYSTEM.

FILED :uuzzo. 1922. 5 SHEETS-SHEET a.

Feb. 27, 1923. 1,446,582.

I W e/11hr. 14pm Po/m/m WSAM a an "T? a P in a $31 is. l

passer YORK.

ASSIGNOR T0 WESTERN ELECTRIC N. Y., A CORPORATION OF NEW OALL-DISTEIBUTING SYST'ENE.

Application filed June 20. i922.

To (all to item 2'23 may concern:

Be it known that l, LIPA Pomn nowsiir. a citizen or Russia, residing at 1 Rue du Bastion in the city oi Antwerp, Belgium. have invented certain new and useful Improvements in Call-Distributing systems (for which I have filed an appli ation in Great Britain June 10, 1921, No. 16,037 1921), or which the following is a full. clear. concise and exact description.

This invei tion relates to telephone systems. and particularly to a call distribution system for uniformly distributing calls received from the subscribers of the system over number or operators positions.

It is the object of the present invention to provide an improved system of this character.

In carrying out the invention it is proposed to improve the distribution of the calls by classifying the different operators with regard to the reception of the calls according: to their availability for service. According to this classification an operator may be "free, may have received one waiting call, two waiting calls, three waiting calls or more and the distributing system is so arranged that upon the initiation of call this call is extended to an operator who .may be regarded as most available for service. For example, if certain of the operatorshave two waiting calls upon their position not yet attended to and the remainder only one waiting calh a call initiated during this condition will be extended to an operator having only one waiting call. It the operators are equally loaded further calls are equally distributed over all the positions.

This equal distribution is. according to the particular embodiment of the present invention hereinafter fully described carried up to three waiting calls as this has been found sufiicient for practical purposes. but it will be fully understood that the equal distribution may be effected up to any number of waiting calls desired. Further, immediately call is received upon an operatofis position. this position is held unavailable for a definite period of time, determined by means hereinafter fully described, and during this period of time no calls may be extended to this position under any circumstances whatever.

Serial No. 568,63

According to a further feature of the invention it is arranged that after a position has received a definite number of waiting calls the position is classified as such and remains classified as having this number of waiting calls until all these calls have been cleared. in this way an operator who becomes overloaded is given an opportunity to clear her position of waiting calls and the subscribers waiting for the operators attention will be attended to more quickly than it calls continue to arrive at this position.

In the practical embodiment of the invention hereinafter described first line finder switches are provided for connecting a calling' line of a group of subscribers lines. These first call finder switches are divided into subgroups which are connected with different groups of second line finder switches. Each second line finder switch forms part of an operators cord circuit. one end of this cord circuit terminating in a second line finder switch, the other end in a first group selector.

According to a further feature of the invention the call distributing; system consists of relays only, in contrast with systems heretofore proposed employing automatic switches. T he use of relays only ensures exceedingly rapid operation and avoids the faulty distribution obtaining in systems employing automatic switches due to the time involved in the operation ot the switches.

The invention will be fu ly understood from the following description of one specitic embodiment taken in connection with the accompanying drawings. Fig. 1 shows diagrammatically av calling line and afirst line finder and the controlling relays tor a group of such finders.

Figs. 2 and 3 show a. cord circuit terminatinc; in a second line finder switcln a first selector switch. and. a called line.

Figs. and show the controlling apparatus located at the operators position tog ther with the relays effecting the equal distribution ot the calls. The drawings should be placed with Figure 2 to the right oi Figure 1, Figure 3 to the right of Figure 2, and Figures l and 5 below Figures 2 and 3 respectively, with the adjacent corresponding conductors in alignment.

The system described is of the welldrnown semi-automatic type in which upon a line calling, the line is connected automatica ly by first and second line finder switches to an operators cord circuit. A register choosing switch associated with the cord circuit auto matically operates to select an operators registering and controlling mechanism which is then connected with the cord. The operator obtains the number of the desired line. from the calling subscriber and registers the designation of the line upon a keyboard which thereupon controls the operation of the registering and controlling mechanism or sender to determine the subsequent operation of the selector switches in the extension of the call.

The first line finder switches, of which the brushes 26. 27, 28 and 29 of one are shown in 1, have a large number of contacts for example, sixty sets. in their banks and are, therefore. capable of accommodating this number of subscribers lines which may be regarded a group of subscribers. The number of first line finder switches serv ing such a group of subscribers will be termed a group of first line finders and such a group is divided into subgroups for eX ample, three, connected with different groups oi. second. line finders on which the brushes 253,254, 255 and 256 of one are shown in 2 of the drawings. Such second line finders have a similar number oi contacts in their banks, and are, therefore, capable of acconzrnooatine. say. sixty trun s extending from the first line finders. The second line finder switch shown forms part of a cord circuit. the other end of the cord circuit shown in Fi 3 terminatin in a first se- P (5 iii It will lector switch, and the number of such cords serving a number of firstline finder switches maybe termed a group of cords and three such. groups may be termed a. super-group. Each group of cords is in turn divided into subgroups and each operator has at her dispos'al one or more subgroups of cords from a number of super-groups of connecting cir cuits. A sub-group of cords may consist,

, for example, of three cords. A, group of operators may be termed a team.

The call distributing relays shown to the left of Figure 4 determine that o .ly the tre first line finders of those sub-groups which have access to free second line finders of the cords associated with free operators positions maybe operated to search for a calling line. When all the operators positions are busy and further calls arrive, one waiting *allis distributed to each operators position. This equal distribution is extended up to a definite number of calls, in the particular example described, three.

It is believed that the invention is of such a character as will be fully understood from a description of the operation oi? the system. e understood that the sequence messes switch elements shown in the cord circuit Fig. 2 and Fig. 3 areall controlled in the well-known manner by the sequence switch 220. The numbers attached to the contacts indicate when these contacts are closed eX- cept those numbers attached to the local contact which indicate the positions in which this is open. The timing sequence switch 3520 indicated within the rectangle at the bottom of Figure d controls the elements therein.

Each operators position is provided with an operatoi"s busy relay 303 Figure t which, when operated, determines that the tree second line finders of the cord circuits associa'ed with this position may hunt for a calling line and brin in a call upon the OPQI'EIiOZ S po ion. The relay 803 controls the circuit or relays, such as relay 812,0ne. of which is provided for each two'suhgroups o s cond line finder switches asso ciated with the operators position.

When an operator at her position a key is thrown or plug inserted which causes the energization of the operators relay Slit this; circuit being traceable from battery, re sistance 30]. winding of relay 300. through the operatofis transmitter 302 to earth. Helay 30(l upon operating, closes the circuitfor the luisycontrol relay 303 which may be traceo t'roin battery, through its winding. .ri 'ht-hand upper iightand left-hand contacts of .cnt 306 oat timing sequence switch 320, which normally rests in position 6, 12 or 1.8 hack contact 398, and 371 and armature 397. 38 and lit) o't relays 307, 308, 809 respectivey to e rth. The busy control relay 3J3. upon energizing, close a locking circuit itselt earth through its contact 31]., armature ill) and back contact 356 and. armature 395 of relay 363 independont of the contacts oi element 305 anc, he Elli 30S and and also for the relayI-llQ and other '-.iihir to relay 3332 in parallel theres hetero e lained. one relay such 7 aided for each two subsecond' line .inders and a number relays are provided. controlled. by

the rc ar i 5 accordin the second line findc the operatofis oi the circu the sub-groups o1" which have access to position illustrator. in l qz \in 's. Relay also cloz s sequence switch 320 which circuit may is traced. from battery,

l winding}: of this 5.1m,

l. which is one of the operative positions of the switch, indicating that the operator is z t her position and ready to receive a call. call may be received also in positions Fuon a subscriber, for example the subscriber A of line 1, 2, Fig. 1 initiating a call he removes his receiver and the line relay 3 is energized over the loop in the usual manner and closes a circuit for the calling relay 4, one or" which is provided tor each group of subscribers lines. Upon the calling: relay 4- energizing, circuit is -losed for the call helping relay 5 in an obvious manner and this relay, one or. which is provided, for example, or every n ne first line finders closes a circuit :tor

Lie subgroup relays, such as 6, one such sub-group relay l'ieing provided for en:-

every three first line finders. .L. LO?

ample, for

The circuit relay 6 may be traced from bat e I r contact 33.7, and armature 318 or relay lili Figure 4: armature l and trout contact 11 of relay 5, Figure it winding: of relay 6 to earth. Belay 319 in iv dualt-o a group 0%? second line finder switches is energized whenever one of the second line tinder switches of the cords is in its normal position, that is to say its controlling sequence switch 22 ,Flgt1l'8 2, st nds in position 1 and a relay such as Figure l, is energized indicating that a call may be received upon an operators position with which the second. line finder is associated. The circuit for the relay 319 may be traced from. battery, through its winding, front contact 321 and armature of relay 312, lower left-hand contact of element 2% 0:" sequence switch 220 in position L. to earth. The relays 329 and 339 are similarly energized so long a cord circuit is available and an operators positi to which they have access may receive a call. 7 I

The relay 6, upon energizing" closes circuit of the power u'iagnets otthe 1:1, line finders in this sub-group the brushes 26 27, 2S and 29 of one of which are illustrated in Fig. 1. This circuit may be traced from battery armature 14-, and baclr contact 15 of relay 16, armature 17 and beer conof relay 19 winding of the power 21 and 22 0t jaclrflf-l n {he 20, springs contact 2% and armature 25 of relay 6 to ea *1. The power magnet thereupon operates to rotate the brushes 26, 27, 28,

in search of the calling line and when "his is found the test relay 3O GZlBITglZGS in the well-known inanner due to the poten lial on the test terminah and inturn causes the'energization of the relay 19 which is of low resistance and causes the calling line test busy to other switches. Relay 19, 5 1 energizing, opens the circuit, betore cured of the power magnet 20 thereby bringing the brushes 26 to 29 to rest upon the contacts of the calling line and closes traced from cry, arnia tact l5 of j 16. armature contact :32 or relay 1.), Wll'lCllIl l l conand front of Holding;

magnet and winding of the ailing): relay 33 ot the second line finder switches to eartlr The connection the low resistance relay 19 in parallel with the windot the callir relay r causes this relay to deenergz ize thereby deenergizing the relays 5 and 6 and bringing all the other first line finders which scarchi: tor the ,-allline to rest. The hclcv ierates to hold the brushes in p tact with the contacts of the C4 in the well-lniown manner.

Ore calling relay, such relay 33 is provided for each group or second line finders and this relay upon energizing- Jetore described closes the circ its helping:

- in an obvious a and relay 2? o e *ord circuit show: cui; may be traced orn buttery. fl) and Front contactoi relay cu being; as elenien when it may be traced from the upper I contact of this element.

winding contact or so armature relay, 23L

The

earth throne earth, locks itself to ins contact iGl and armature circuit closed for the power magoil the second line finder switch rroin battery windi s i 7" lower lettshand con- 8, front contact 9 s9, and relay 230, trout c intact of relay 231 to earth. wer et 24:7 thereupon operates the brunes 253 and 256 nd line finder to rotate in search Jlli extending;- trons the first line ioh when this trunk is found relay is operated in the usual i ianner to open the -ircuit of the line relay N0 which turn ale/energizes opens the circuit oi the power magnet 24'? thereby br' gi li the wipers to rest upon the terminals o]: the desired trunl: line.

Upon the relay 230 deenergizing a circ v c for driving the sequence switch ll cord circuit out of position This nature w, w w, l. and, 2 2 lllziolll 6 i i 1 01 L110 iii) circuit may be traced from battery, windof' sequence switch 220 and its locontact right-hand lower contact element 253, back contact 259 and armature 250 of relay 230, contact 251 and armature 252 of relay 231 to earth. The sequence switch 220 thereupon moves from position 1 and under the control of its local contact moves into position 3 where it comes to rest. In this position a circuit is closed for the register selecting sequence .';WltCl'l 262 and this switch thereupon opers in the welleknown manner to select an -storing mechanism not shown. The contacts shown below the broken line in Figures 2 and are controlled by sequence switch 262. the leads 200, 201,202, 203, 205 and 206 extending to a registering mechanism of a character well known in the art adapted to be operated to record the designation of the called line.

When the second line finder switch brings in a call the incoming call. relay 363 at the operators position is energized over a circuit extending from battery, winding of relay contacts of key 330, holding magnet 207 of the second line finder switch, upper left and lower right-hand contacts of element 258, back contact 259 and armature 250 of relay 230, contact 251 and armature 252 of relay 231. to earth. Relay 363 opens the circuit before traced for the relay 303 at its back contact 356. Relay 303 there upon deenergizes and opens the circuit of the busy position relays such as 312, and the deenergization of these relays determines n that no further calls for the time being may car be received upon the operators position. Relay 303 upon deenergizing closes the circuit for toe timing sequence switch 320 which may be traced from battery, winding of this sequence switch, upper righthand contact ofits element 353, contacts of key 314, back contact 315 and armature 316 of relay 303 to earth. The timing sequence switch 320, which it has been assumed to be standing in position 1, thereupon leaves this position and under the control of its local contact 313 moves into position 2. In position 2 a circuit is closed for the timing relay which may be traced from battery. winding of the relay, lower rio'ht and leftdiand contacts of element 300, inter-- rupter 336 to earth. The interrupter 336 is a1" anged alternately to open and close the circuit of the relay and upon its first energization a circuit is closed for the timing sequence switch 320 which may be traced from battery, through its winding and local contact 313, lower left-hand contact of element front contact. 337 and armature of relay 335 to earth. The timing sequence switch 320 thereupon leaves position 2 and under the control of its local contact 313 moves into position 3. When the interrupter reaches a position in which the circuit of the relay 335 is open this relay deenergizes and a circuit is closed through the armature 338 and the back contact 343 ofthe relay for thetiming switch 320 which thereupon moves into position 4:. In this manner the sequence switch 320 moves step-by-step under the control of the interrupter 336 and the relay until position 6 is reached.

7 ln position 6 of the sequence switch. 320 the sition 3duringthe time the register choos ing sequencel switch 262 is searching for an idle registering mechanism the relay 309 or the operators equipment is energized in a circuit extending" from battery, winding or relay 309, lower left-hand contact of ele ment 226, to earth. Relay 309, upon energizing, opens the energizing circuit of the relay 303 so that relay 303 cannot beenergized. again, although the timing sequence switch 320 is in position 6, 12 or 18, until an idle register has been found and the relay 309 deenergized'by the movement of the sequence switch 220 from position 3. The deenergized condition of the relay 303 causes relay 312 to remain deenergized'in turn and p.re-' vents any' further calls coming into the operators position except ashereinafter described. v

lVhen the sequence switch 220 reaches position 2 a. circuit is closed from battery, call ing lamp 323, Figure 1, lower right and upper left contact of element 232, Figure 2, to earth. The calling lamp glows, indicatto the operator that a call has arrived upon herposition. WVheu the register choosing sequence switch 262 finds a free register or sender the sequence switch 220 moves to position 4 and in this position the inter rupter 233 is connected in series with the calling lamp 323 so that the lamp is then flashed intermittently. When the sequence switch 220 moves from position 3 the circuit before traced fort-he relay 309 is opened at the lower left-hand contact of the element 226 so that this relay is deenergized. While therelay 309 was energized the first waiting call lamp 3'? 5 is energized in a circuit extending from battery, lamp 375, contact 376 and armature 377 of relay 308, contact 378 and armature 370 of relay 309 to earth. The lamp 375 indicated that acall had arrived and a register was being hunted for. If a further call is initiated during the time the relay 309 is energized, the call will be diverted from the operators position shown and will be received at some other operators position provided there is such a position tree and available. Should. however, all the cords of a super group he held busy due to the deenergization oi the relay 303 at each operators position the relays 319, 329 and 339 will be die-energized. Upon the energization of the relay when a turther call initiated during this condition a circuit is closed from battery. front contact 5 .2 and armature of relay l in' re 1, armature and back contact 3411 of rs lay 319, Figure armature 3 1T and back contact 341 8 of relay 329, armature 348 and back contact 349 of relay 339. windings of relay 34:0 and 341 to earth. Relay 3&1. upon energizing, by closing its armature and front contact 381 provides an alternatiie energizing circuit for the relay to that provided through the armature 3'70 and contact 371 of the relay 309 and it there is a cord circuit available, that is, it iere a cord circuit having its sequence si ch 220 standing in position 1, a circuit is closed for the relay 303 which may be traced from battery, through its winding, contacts of rclay 300 and relay 30 1, upper right and lefthand contacts or": element 305. assumed to have been driven from position 1 to position 6, contact 398 and armature 39'? oi relay 307, contact 385 and armature 384; oi

relay 308, armature 359 and front contact 381 of relay 341, back contact and mature 322 of relay 312, lower lefthand contact or element 226, to earth.

Belay 303 thereupon energizes and closes a circuit for the relays 312 so that a furher call may be received upon the (hoorators position, upon the energization of relay 341, Figure 1. although a call already needs attention thereupon. ii second line finder switch thereupon operates to connect with the trunk extending from the first linc finder switch which has connected with the calling line and the relay 363 at the operators position is energized as hetore de scribed and as it is assumed that the re 3 309 is still energized owing to the first waiting call not having been connected with a registering mechanism, a circuit is closed for the second waiting call relay which may be traced from batter armature and front contact 391 of relay 309. wind up of relay 308, back contact and armature 393 of relay 380. contact 39% and armature 395 of relay 363 to earth. The relay upon energizing. opens the circuit of the first waiting call lamp and closes the circuit or the second waiting; call lain 386, which circuit may be traced from battery, lamp 386, back contact 388, and armature 387 of relay 307, front contact 389, and armature 377 of relay 308, contact 378 and 385 and ari'natu 384 controlled armature 370 of relay 309 to earth. 'lhe second waiting call lamp 386 thereupon glows and indicates to the operator that a second waiting call has arri ed upon her position.

The second waiting; call energizing also opens, at i.. u, and contact the circuit or the re so that the circuit of this relay is opened at two points. that is, at contacts by relay 308 and at contact 371 and armature 3. 0 of relay 309. It all. the other operators positions are loaded to an equal extent and another call is initiated, the relays 319, 329

and 339 will be deenergized as heiore described. The energizing of the role;' 5 upon the initiation of this further call will therefore cause the energization of the re lays 340 and 3 1-1 as betore described and relay will, by closing armature and 381. provide an alternative path for t cncrgizing circuit for the relay to the circuit extending; thron h the armature 370 and contact 371 ct rel y 309. This alterna tive path. however, is unable to complete the energizing circuit of the as its circuit is opened explained at the contact 385 and armature ot the second waiting call relay 308. The relay remains deenergized and thereto-re does not cause the energization ot the relay 319 which in turn maintains the relays and 341 energized. The relay closes the circuit-ct the SlOWw'C-QQGTQlZG relay 350 which may be traced. from batte winding of relay 350, contact and armature of relay 340 to earth. The relay attracts its armature short time at its circuit is closed so that a circuit is now closed tor the second pair of (ilSi'lllNlilZ-lfjj relays 354 and 355 wh ch may traced from battery. contact and arina ll'O -13 0t relay 5, Figure ariuaturcs 34-5. 347. 3 18 and. back contactm and 34-9 ot relays 319. 329 e39 ipict cly. contact 366 and armature of relay 350. WlDCllJQS oi relays 354 a 355 by clos. shunts the 308 enbut upon enere zinci and a r The relay its contact 1 contact and arm 'ure of relay so that now the relay may be gain erg'ized over the circuit hetero traced, including the armature and contactin place of the contact and armature of the second waiting cal relay 308.

The relay 33 upon energizing energizes the relay 312 and provided there are cord circuits free the second line tinder switches thereof will operate, upon the energization of the relay 34L, to search for the trunk extending from the first line finder switch which has found the calling line. When a second line finder switch finds the trunk and the relay 363 is energized as before described, a circuit is closed for the third waiting call relay 307 which may be traced from battery, armature 390 and contact 391 of relay 309, winding of relay 307, front con tact 392 and armature 393 of relay 380 (relay 380 having been energized upon the energization of relay 308 over a circuit from battery, armature 390 and contact 391 of re lay 309, winding of relay308, contact 369 and armature 396 of relay 308, winding of relay 380 to earth) contact 394iand armature 395 of relay ?;3 to earth. The relay 307 upon energizing closes a circuit from battery, third waiting call lamp 399; contact 334 and armature 387 of relay 307 contact 339 and armature 377 relay 308. contact 378 and armature 370 of relay 309 to earth. The lamp 399 glows and indicates to the operator that a third waiting call has arrived upon her position.

The relay ,307, upon energizing, opens the circuit of the relay 303 at a third point, namely at its contact 398' and armature 397. If therefore a further call is initiated and the energization of the distributing relays 34:0, 341, 354 and is unable to effect the energization of the relay 303, the slow-toenergize relay 360 is energized by a circuit closed through contact v361 and armature 362 of relay 354. The relay 360 extends the circuit before traced from battery, contact 42 and armature as of relay 5, armatures 345, 34:7 and 3 18 and contacts 344, 3 16' and 349 of relays 319, 329 and 339 respectively, contact 366 and armature 324- of relay 350, contact 36 1 and armature 3250f relay 360, winding of relay 365 and 326 to earth. Relay 326 by closing armature 367 and contact 368 provides a shunt for the contact 398 and armature 397 of relay 307 so that further calls may be received provided there is a free cord by the energization of therelay 303 even although each position has three waiting calls thereon. Such further calls. howlever, will not be equally distributed over the operators positions, the even distribution according to the specific method described of carrying the present'invention into effect being up to three waiting calls only, which is sufiicient for all practical purposes. Upon the relay 307 energizing it closes a locking circuit for itself through its armature 306 and contact 327, this locking circuit being controlled by the relay 309 at its contact 391 and armature 390 so that the relay 307 remains energized until the register sequence switch ceases to search for a register, that is, until there are no further waiting calls upon the operators position. In this way the operators positions which have received three waiting calls remain classi- .fied as having this number of waiting calls thereupon, the third waiting call lamps 399 being lit, nntil all the calls thereupon have been cleared, which will be indicated by the relay 309 deenergizing. Further, by the waiting call lamps provided the condition of any particular operators position may be ascertained immediately, a supervisor being' informed whether the position has one, two or three waiting calls thereupon. 7

It will be seen that a very eliicient call distribution system has been provided. The use of relays only causes the system to act exceedingly quickly effecting aneven and accurate distribution of the calls.

lVhat is claimed is:

1. In a call distribution system, a plurality of operators positions, a plurality of cord circuits ateach of said positions, means for extending calls to said cord circuits, relays individual to each operators position for marking the said position as busy and for barring the further extension of calls to other cord circuits on the same position while a call remains unanswered,

means responsive thereto for maintaining said artificial busy condition for a predetermined length of'time, relays for marking said cord circuits as busy after calls extended thereto have been answered, means responsive to the number of unanswered calls on each of said operators positions for measuring the degree of availability of each of said positions, and means for extending additional calls to said cord circuits in the order of the availability of said positions. I

2. In a call distribution system, a plurality of operators positions, a plurality of cord circuits at each or" saidpositions, means for extending calls to said cord circuits, relays individual to each operators position for marking the said position as busy and for barring the further extension of calls to other cord circuits on the same position while acall remains unanswered,

means responsive thereto for maintaining said artificial busy condition for a prede termined length oi time, relays for marking said cord circuits as busy after calls extended thereto have been answered, means responsive to the number of unanswered calls on each of said operators positions for measuring the degree or. availability of each of said positions, means for indicating the number of unanswered calls on each-of said positions, and means for extending additional calls to said cord circuits in the order oi. the availability of said positions.

In witness whereof, I hereunto subscribe name this 1st day of June A. D., 1922. LIPA POLINKOVVSKY. 

